A password is used for user authentication to gain access to a resource. In modern times, passwords are commonly used by people during a log-in process that controls access to protected computer operating systems, mobile phones, cable TV decoders, automated teller machines (ATMs), etc. A typical computer user has passwords for many purposes: logging into accounts, retrieving e-mail, accessing applications, databases, networks, and web sites.
“Password aging” is a feature of some electronic systems. Password aging forces users to change passwords frequently (e.g., quarterly, monthly, or even more often). Password aging policies are widely used as they are one of only a few built-in policy mechanisms in some systems, for example, a laptop device, a mobile device, email/intranet account, and access to servers.